+3.60 nC of charge is uniformly distributed along the top half of a thin rod of total length L = 4.30 cm, while -3.60 nC of charge is uniformly distributed along the bottom half of the rod, as shown in the figure. What is the magnitude of the electric field at the dot, a distance r= 15.4 cm from the centre of the rod? Magnitude: + +++ + + L r